Bad 02 Sensors
02-08-2007, 07:13 PM
#1
5th Gear Member
Thread Starter
Join Date: Aug 2006
Location: Central Texas
Posts: 3,074
Bad 02 Sensors
What would be some of the signs of bad 02 sensors. I told my mechanic the things my car was doing and he suggested my 02 sensors me be bad. I'd like to get an opinion from you guys if you don't mind.
02-08-2007, 07:34 PM
#2
6th Gear Member
Join Date: Jun 2006
Location: Maine
Posts: 5,693
RE: Bad 02 Sensors
Wouldn't it be easier to tell us what is wrong and we cna tell you if bad O2 sensors would cause that? 
Some common things that may happen... a CEL that goes off and on, running rough, loping, rough idle...
Also, you car will go into limp mode if the CEL gets triggered, so you'll get a loss of power / performance.
Some common things that may happen... a CEL that goes off and on, running rough, loping, rough idle...
Also, you car will go into limp mode if the CEL gets triggered, so you'll get a loss of power / performance.
02-08-2007, 09:51 PM
#3
RE: Bad 02 Sensors
I just replaced one in my wifes 96'
It was running rich and getting horrible economy, it had lost about 15hp in limp mode and stumbled in 3rd-5th gear a lot.
In extreemly cold weather (0-25) it would try to die while cruising on the freeway like it was running outta gas.
Lets see thats just about it.
If it only happens to you while the car is cold untill it warms up then you probably have a problem with the heater coil inside the O2 sensor, it needs to get heated up before running correctly, in which case you would also need to replace it.
You will have a much easier time renting an O2 sensorsocket from AutoZoneinstead ofusing a wrech. You should also use their OBDII reader too to see what codes are being stored in the EEC, just because the Check engine light may not be on doesnt mean that codes arent being stored.
Two ways to fix a bad O2...
1.) replace it with a stock one.
2.) replace it and the other side with MIL eliminators (Rear only)
And of course when working on your car disconnect the battery (It is also important to do so to wipe the code from the system.)
Best of luck.
-Eric-
It was running rich and getting horrible economy, it had lost about 15hp in limp mode and stumbled in 3rd-5th gear a lot.
In extreemly cold weather (0-25) it would try to die while cruising on the freeway like it was running outta gas.
Lets see thats just about it.
If it only happens to you while the car is cold untill it warms up then you probably have a problem with the heater coil inside the O2 sensor, it needs to get heated up before running correctly, in which case you would also need to replace it.
You will have a much easier time renting an O2 sensorsocket from AutoZoneinstead ofusing a wrech. You should also use their OBDII reader too to see what codes are being stored in the EEC, just because the Check engine light may not be on doesnt mean that codes arent being stored.
Two ways to fix a bad O2...
1.) replace it with a stock one.
2.) replace it and the other side with MIL eliminators (Rear only)
And of course when working on your car disconnect the battery (It is also important to do so to wipe the code from the system.)
Best of luck.
-Eric-
02-09-2007, 12:58 AM
#4
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
RE: Bad 02 Sensors
As related above, a typically bad narrowband O2 sensorappears tothe PCM as a high-value variable resistor (I.e. a zero or very low volt source) which the PCM interprets as a very lean mix--the PCM responds by enriching the air/fuel mix which causes bogging and poor fuel economy. Often the PCM cannot detect that the sensor is failing, it just thinks the mix is lean and compensates as described above...[/align][/align][/align]
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